| OCR Text |
Show 36 PROF. D'ARCY Wr. THOMPSON ON THE [Jan.17, nterrupted ; the postfrontal process is larger and arches downwards ; the squamosal process is very stout, and it* outer surface is practically continuous with that of the low, broad, suprameatal process. The auditory meatus is wide open and nearly square; the basitemporal plate is much smaller relatively, and scarcely larger actually than in Geoffroyus: and the surfaces lateral to it are correspondingly broad. The two heads of the quadrate are confluent; the anterior or pterygoid process of the same bone is unusually large. The mandibular fontanelle is obsolete. Ihe intraorbital fissures are unusually small. Fig. 34. Pyrrhulopsis personata. Fig. 35. Auditory region of Pyrrhulopsis. Pyrrhulopsis, Aprosmictus,a,nd Polytelis differ from Tanygnathus several points, and particularly in the region of the postorbital and squamosal processes. The postorbital is very indistinctly defined, and exists only as the thickened edge of the descending posterior rim of the orbit, where it meets the temporal fossa. It descends lower in Aprosmictus than in Pyrrhulopsis,and lower still in Polytelis, where it leaves only a slight and narrow groove between it and the squamosal to represent the outlet of the fossa. The configuration of the base of the squamosal process is totally different from that of Tanygnathus; for the suprameatal process is now separated by a wide and deep groove from the squamosal, and the latter does |
